4. Intangible Assets, Goodwill and Other (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Jun. 30, 2020	Sep. 30, 2020	Dec. 31, 2019
Goodwill [Line Items]
Goodwill		$ 627,100	$ 599,300
Accumulated impairment loss		(335,200)	(335,200)
Goodwill, net		291,916	264,131
Goodwill, Acquired During Period	$ 29,800	29,800
Goodwill, Other Increase (Decrease)		2,000
Life Science [Member]
Goodwill [Line Items]
Goodwill		277,900	250,100
Accumulated impairment loss		(41,800)	(41,800)
Goodwill, net		236,100	208,300
Goodwill, Acquired During Period	29,800	29,800
Goodwill, Other Increase (Decrease)	$ 2,000	2,000
Clinical Diagnostics [Member]
Goodwill [Line Items]
Goodwill		349,200	349,200
Accumulated impairment loss		(293,400)	(293,400)
Goodwill, net		55,800	$ 55,800
Goodwill, Acquired During Period		0
Goodwill, Other Increase (Decrease)		$ 0